/* 全局样式 */
:root {
  --primary-color: #1890ff;
  --secondary-color: #f0f2f5;
  --text-color: #333;
  --text-light: #666;
  --white: #fff;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  --border-radius: 4px;
}

/* 应用容器 */
.app-container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* 顶部导航 */
.app-header {
  background-color: var(--white);
  box-shadow: var(--shadow);
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.logo {
  font-size: 24px;
  font-weight: bold;
  color: var(--primary-color);
}

.main-nav {
  display: flex;
  gap: 32px;
}

.nav-item {
  color: var(--text-color);
  text-decoration: none;
  font-size: 16px;
  padding: 8px 0;
  position: relative;
}

.nav-item:hover {
  color: var(--primary-color);
}

.nav-item.active {
  color: var(--primary-color);
}

.nav-item.active::after {
  transform: scaleX(1);
  transform-origin: left;
}

.nav-item::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--primary-color);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.nav-item:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.user-controls {
  display: flex;
  gap: 12px;
}

.btn-login, .btn-register {
  padding: 8px 20px;
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  font-size: 14px;
  transition: all 0.3s ease;
}

.btn-login {
  background-color: transparent;
  color: var(--text-color);
  border: 1px solid #d9d9d9;
}

.btn-login:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
}

.btn-register {
  background-color: var(--primary-color);
  color: var(--white);
}

.btn-register:hover {
  background-color: #40a9ff;
}

/* 用户个人资料 */
.user-profile {
  display: flex;
  align-items: center;
  gap: 12px;
}

.user-email {
  color: var(--text-color);
  font-size: 14px;
}

.btn-logout {
  padding: 6px 16px;
  background-color: transparent;
  color: var(--text-light);
  border: 1px solid #d9d9d9;
  border-radius: var(--border-radius);
  cursor: pointer;
  font-size: 14px;
  transition: all 0.3s ease;
}

.btn-logout:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
}

/* 主要内容区域 */
.app-main {
  flex: 1;
  padding: 24px;
}

/* 歌曲卡片样式 */
.song-card {
  background-color: var(--white);
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.song-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

.song-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.song-card .song-info {
  padding: 16px;
}

.song-card .song-title {
  font-size: 16px;
  font-weight: 500;
  /* margin-bottom: 8px; */
  color: var(--text-color);
}

.song-card .song-artist {
  font-size: 14px;
  color: var(--text-light);
}

/* 响应式设计 */
@media (max-width: 768px) {
  .app-header {
    padding: 0 16px;
  }
  
  .main-nav {
    gap: 16px;
  }
  
  .nav-item {
    font-size: 14px;
  }
  
  .app-main {
    padding: 16px;
  }
}